In many cases, it is OK to show slightly different content on different devices. For example, optimizing the smaller space of a smartphone screen can mean that some content, like images, will have to be modified. Or you might want to store your website’s menu in a navigation drawer (find documentation here) to make mobile browsing easier and more effective. When implemented properly, these user-centric modifications can be understood very well by Google.

The situation is similar when it comes to mobile-only redirect. Redirecting mobile users to improve their mobile experience (like redirecting mobile users from example.com/url1 to m.example.com/url1) is often beneficial to them. But redirecting mobile users sneakily to a different content is bad for user experience and is against Google’s webmaster guidelines.

A frustrating experience: The same URL shows up in search results pages on desktop and on mobile. When a user clicks on this result on their desktop computer, the URL opens normally. However, when clicking on the same result on a smartphone, a redirect happens and an unrelated URL loads.

Who implements these mobile-only sneaky redirects?

There are cases where webmasters knowingly decide to put into place redirection rules for their mobile users. This is typically a webmaster guidelines violation, and we do take manual action against it when it harms Google users’ experience (see last section of this article).

But we’ve also observed situations where mobile-only sneaky redirects happen without site owners being aware of it:

Advertising schemes that redirect mobile users specificallyA script/element installed to display ads and monetize content might be redirecting mobile users to a completely different site without the webmaster being aware of it.

Mobile redirect as a result of the site being a target of hackingIn other cases, if your website has been hacked, a potential result can be redirects to spammy domains for mobile users only.

How do I detect if my site is doing sneaky mobile redirects?

Check if you are redirected when you navigate to your site on your smartphoneWe recommend you to check the mobile user experience of your site by visiting your pages from Google search results with a smartphone. When debugging, mobile emulation in desktop browsers is handy, mostly because you can test for many different devices. You can, for example, do it straight from your browser in Chrome, Firefox or Safari (for the latter, make sure you have enabled the “Show Develop menu in menu bar” feature).

Listen to your usersYour users could see your site in a different way than you do. It’s always important to pay attention to user complaints, so you can hear of any issue related to mobile UX.

Monitor your users in your site’s analytics dataUnusual mobile user activity could be detected by looking at some of the data held in your website's analytics data. For example, looking at the average time spent on your site by your mobile users could be a good signal to watch: if all of a sudden, your mobile users (and only them) start spending much less time on your site than they used to, there might be an issue related to mobile redirections.

To be aware of wide changes in mobile user activity as soon as they happen, you can for example set up Google Analytics alerts. For example, you can set an alert to be warned in case of a sharp drop in average time spent on your site by mobile users, or a drop in mobile users (always take into account that big changes in those metrics are not a clear, direct signal that your site is doing mobile sneaky redirects).

I’ve detected sneaky redirects for my mobile users, and I did not set it up: what do I do?

Audit third-party scripts/elements on your siteIf your site is not hacked, then we recommend you take the time to investigate if third-party scripts/elements are causing the redirects. You can follow these steps: A. Remove one by one the third-party scripts/elements you do not control from the redirecting page(s). B. Check your site on a mobile device or through emulation between each script/element removal, and see when the redirect stops. C. If you think a particular script/element is responsible for the sneaky redirect, consider removing it from your site, and debugging the issue with the script/element provider.

Last Thoughts on Sneaky Mobile Redirects

It's a violation of the Google Webmaster Guidelines to redirect a user to a page with the intent of displaying content other than what was made available to the search engine crawler (more information on sneaky redirects). To ensure quality search results for our users, the Google Search Quality team can take action on such sites, including removal of URLs from our index. When we take manual action, we send a message to the site owner via Search Console. Therefore, make sure you’ve set up a Search Console account.

Be sure to choose advertisers who are transparent on how they handle user traffic, to avoid unknowingly redirecting your own users. If you are interested in trust-building in the online advertising space, you may check out industry-wide best practices when participating in ad networks. For example, the Trustworthy Accountability Group’s (Interactive Advertising Bureau) Inventory Quality Guidelines are a good place to start. There are many ways to monetize your content with mobile solutions that provide a high quality user experience, be sure to use them.